Standard enthalpies of formation of perfluoro(2-methyl-3-oxa)hexanoic and perfluoro(2,5-dimethyl-3,6-dioxa)nonanoic acids

The energies of combustion of perfluoro(2-methyl-3-oxa)hexanoic and perfluoro(2,5-dimethyl-3,6-dioxa)nonanoic acids are for the first time measured in a calorimeter with a rotating platinized bomb and used to calculate the standard enthalpies of formation of these compounds in the liquid state. Based on the enthalpies of formation, the contribution from the [-CF₂OCF(CF₃)-] group to the enthalpies of formation of perfluoro acids is calculated.     

Comparative analysis of cytotoxic effects and intracellular accumulation of platinum(IV) nitroxyl complexes

Russian Chemical Bulletin - The relationship between the lipophilicity, cytotoxic effects, and intracellular accumulation for potential antitumor agents, viz., amino complexes of platinum(IV) with...     

The standard enthalpy of formation of silver pivalate

The standard enthalpy of combustion of crystalline silver pivalate, (CH₃)₃CC(O)OAg (AgPiv), was determined in an isoperibolic calorimeter with a self-sealing steel bomb, Δ_c H ⁰ (AgPiv, cr)= −2786.9±5.6 kJ mol⁻¹. The value of standard enthalpy of formation was derived for crystalline state: Δ_f H ⁰(AgPiv,cr)= −466.9±5.6 kJ mol⁻¹. Using the enthalpy of sublimation, measured earlier, the enthalpy of formation of gaseous dimer was obtained: Δ_f H ⁰(Ag₂Piv₂,g)= −787±14 kJ mol⁻¹. The enthalpy of reaction (CH₃)₃CC(O)OAg(cr)=Ag(cr)+(CH₃)₃CC(O)O^.(g) was estimated, Δ_r H ⁰=202 kJ mol⁻¹.     

Sulfate-Sulfide Equilibrium and Contents of Heavy Metals in Bed Sediments in Fresh and Salty Lakes of Altay Region

Sediment quality criteria (SQC) is based on the assumption of bioavailability of heavy metals. Heavy metals are connecting in strong inert complexes are less toxicity and less availability for hydrobions.     

The enthalpy of formation of fullerene fluoride C<Subscript>60</Subscript>F<Subscript>18</Subscript> and the C-F bond energy

The enthalpy of combustion of crystalline fullerene fluoride C₆₀F₁₈ was determined in an isoperibolic calorimeter with a rotating platinized bomb, and the enthalpy of formation of the compound was calculated. The enthalpy of sublimation of C₆₀F₁₈ measured earlier was used to calculate the enthalpy of formation of fullerene fluoride in the gas phase and the mean enthalpy of dissociation of C-F bonds in this compound.     

Standard enthalpy of formation of fullerene bromide C60Br24

The enthalpy of the combustion of C₆₀Br₂₄ · 2Br₂ has been measured using a rotating-bomb calorimeter as follows: Δ _c H ⁰(C₆₀Br₂₄ · 2Br₂, cr) = (?25986 ± 166) kJ/mol. The result has been used to calculate the standard enthalpy of formation, ΔfH ⁰(C₆₀Br₂₄ · 2Br₂, cr) = (2375 ± 166) kJ/mol. The enthalpies of formation of C₆₀Br₂₄ (cr) and dissociation of the C-Br bond have been estimated. The latter value has been compared with enthalpies for the C-X (X = H, F, Cl, Br) bonds in fullerene derivatives and organic compounds.     

Cytostatic action of triazole and oxazolidinone derivatives

We synthesized a number of derivatives of 1,2,3-benzotriazole, 1,2,4-triazole, and oxazolidine-2-one derivatives, among which compounds suppressing the growth of the tumor cells HeLa and H1299 were revealed. The studies of the effect of these compounds on the cell cycle and activity of caspase dependent degradation of poly(ADP-ribose) polymerase showed that these compounds at the IC₅₀ doses exhibit cytostatic effect on tumor cells. In the MCF7 cells, these compounds induce an increase in expression of the tumor suppressor p53.     

Interference caused by indium in the atomization of Ag, Bi, Cd, Sn, and Tl in ETA-AAS

The depression of the signals for Ag, Bi, Cd, Sn, and Tl trace determination by ETA-AAS, which occurs in the presence of hydrobromic acid (with or without indium present), has been investigated by use of a new combined atomization equipment, molecular absorption measurements and thermodynamic calculations. The results show that all these elements form easily volatile bromides and more or less stable diatomic molecules of MBr type. These diatomic molecules, formed in the gaseous phase, are removed from the observation volume by diffusion, before their dissociation is complete. These two effects-formation of easily volatile compounds and stable diatomic molecules-are the main reasons for the depression of the atomic-absorption signals.     

One-pot electrochemical synthesis of acid anhydrides from alcohols

Russian Journal of General Chemistry - One-pot indirect electrochemical oxidation of alcohols in the methylene chloride–aqueous solution of sodium hydrocarbonate two-phase system in the...